In the above-noted prior patent, the entire disclosure of which is incorporated herein by reference and relied upon, a composition is disclosed which has a taste, texture and mouth feel similar to butter but which is spreadable at refrigeration temperatures, e.g. 34.degree. to 45.degree. F., and will not oil-out at room temperatures and above, e.g. 85.degree. F. or even 95.degree. F. The composition comprises a concentrated mixture of at least one water-in-oil emulsion and at least one oil-in-water emulsion of dairy products, where the ratio of water-in-oil emulsion to oil-in-water emulsion is at least 6:4 but is less than about 9:1 and wherein the fat content of the butter-like composition is at least about 40%.
The composition is made by preparing a feed of at least one liquid dairy product which is primarily an oil-in-water emulsion and has a fat content of at least about 8%. The feed is concentrated by removing, primarily, water, lactose and ash until a concentrate having at least about 40% fat is obtained. That concentrate is homogenized and the concentrate is caused to have a phase reversal, either prior to, during or after homogenization, so that the emulsion of the concentrate is converted from a primarily oil-in-water emulsion to a predominantly water-in-oil emulsion, whereby the concentrate forms the butter-like composition, and wherein the ratio of water-in-oil emulsion to oil-in-water emulsion in the composition is at least about 6:4 but is less than about 9:1.
The invention of that prior patent is based on three primary discoveries and several subsidiary discoveries. A first basic discovery in this regard is that all of taste, texture and mouth feel must result from a composition which is predominantly a water-in-oil emulsion.
A second basic discovery of that invention is I0 that the taste, texture and mouth feel of butter results, in part, from butter actually being a combination of a water-in-oil emulsion and an oil-in-water emulsion. While the ability to accurately pinpoint the ratios of the water-in-oil emulsion to oil-in-water emulsion in butter has not been developed, it appears that the ratio in butter is somewhere about 9:1 or above. Unfortunately, however, when that ratio of water-in-oil emulsion to oil-in-water emulsion is about 9:1, or above, the fat phase will crystalize at refrigeration temperature and, thus, will render the composition essentially non-spreadable.
Therefore, as a subsidiary discovery in that invention, it was found that compositions which contain both a water-in-oil emulsion and an oil-in-water emulsion, must have a ratio thereof at or below about 9:1, or otherwise the non-spreadability of butter will also appear in that composition.
On the other hand, as a further subsidiary discovery of that invention, it was found that if that ratio is not at least about 6:4, and preferably about at least 7:3, then the taste, texture and mouth feel does not approximate that of butter. For example, it was found that the composition of U.S. Pat. No. 4,511,591, is actually a mixture of water-in-oil emulsion and oil-in-water emulsion, although the oil-in-water emulsion considerably predominates in that composition. Indeed, it appears that the ratio of water-in-oil emulsion to oil-in-water emulsion in a product of that composition is about 1:5 which, as it turns out, is about the same ratio as cream cheese, thus explaining why that composition has a taste, texture and mouth feel more similar to cream cheese than to butter.
As a further basic discovery, it was found that in order to achieve the taste, texture and mouth feel of butter, the composition must have a fat content of at least about 40% (the remainder being primarily water, milk serum and protein). Otherwise, the composition will have a predominantly watery taste, texture and mouth feel, as opposed to a predominantly fat taste, texture and mouth feel of butter.
As another subsidiary discovery in this regard, it was also found that the composition must be prepared so that essentially all of the fat which ultimately resides in the composition is in the emulsions from which the composition is formed and that fat cannot be added after those emulsions are formed, which is opposite the process in above-mentioned U.S. Pat. No. 4,511,591.
Finally, as a subsidiary discovery in that invention, it was found that in order to achieve these high fat levels, the dairy product from which the composition is made must be considerably concentrated prior to forming the composition; otherwise its high fat levels cannot be obtained, and the resulting composition will not have the taste, texture and mouth feel of butter.
In the process described in the above-noted prior patent, one or more feeds are used to produce a mixture which has a fat content of at least about 8%. The feeds can be any dairy products, so long as those dairy products are in liquid form and so long as those dairy products are primarily oil-in-water emulsions. However, most dairy products, indeed, meet these requirements and, therefore, any of the conventional dairy products may be used, for example, skim milk, low-fat milk, whole milk, non-fat milk solids, and cream and concentrated forms thereof, e.g. evaporated skim milk, whole milk, and cream. Other dairy products, such as buttermilk, could be used, and the particular form of the dairy product is not critical, other than the two reservations noted above. If, for example, skim milk is used as a feed, then a second feed must be used, since skim milk will not provide the necessary fat content of at least about 8%. Accordingly, in this situation, there would be at least two feeds, e.g. one of skim milk and one of cream so that the fat content of the mixture reaches at least about 8%. On the other hand, the amount of fat in the mixture cannot be overly high, since it will interfere with the concentration step. Thus, preferably, the fat content is not above about 30%, although higher fat contents than this may be used, e.g. up to about 35% fat or even a bit higher, if care is taken in the concentration step. Nevertheless, for practical and usual purposes, the fat content of the mixture will not be greater than about 30%.
After the mixture is formed, that mixture must be concentrated so that the concentrate has a fat content of at least about 40%, but more preferably about 50%. The concentrate may have a fat content up to about 60%, or even greater, but at fat contents significantly above 60%, the concentration step becomes more difficult.
The preferred concentration step utilizes ultrafiltration. Any conventional ultrafiltration unit may be used in this regard, and it is only necessary that the ultrafiltration unit retain substantially all of the protein in the concentrate (the protein, in part, functions as the natural emulsifiers), with the permeate containing, primarily, water, lactose and ash. This is achieved by the usual dairy ultrafiltration unit, and, thus, any conventional dairy ultrafiltration unit may be used in the concentrating step. Likewise, conventional temperatures for operating the ultrafiltration unit are quite acceptable, e.g. 100.degree. to 130.degree. F., although temperatures outside of this range may be used, if desired, e.g. 40.degree. to 150.degree. F.
After the concentration step, the resulting concentrate is homogenized. Any of the conventional dairy homogenizers may be used in this regard, and those homogenizers may be operated at conventional temperatures, e.g. 120.degree. to 160.degree. F., although temperatures outside of this range may be used if desired, e.g. 110.degree. to 180.degree. F. However, either prior to, during or after homogenization, the concentrate must experience a phase reversal, i.e. reversing the emulsion from, primarily, an oil-in-water emulsion to, predominantly, a water-in-oil emulsion. This phase reversal can be achieved by any relatively high shear mixing operation. However, since homogenization is a high shear mixing operation, it is more convenient and efficient to achieve at least a portion of the phase reversal during the homogenization step and in the homogenizer. Thus, it is only necessary to operate the conventional dairy homogenizer for a time and at a shear rate which will not only homogenize the product but achieve a portion of the phase reversal at the same time. With the phase reversal, the concentrate forms a butter-like composition which is, essentially, the product of the invention of the prior patent.
With butterfat concentrations of about at least 40%, the phase reversal is relatively easy to achieve in the usual dairy processing apparatus. As the feed is being further and further concentrated during ultrafiltration (the preferred concentration device), and the butterfat content is increased, some phase reversal will commence during ultrafiltration. When the butterfat content, during continued ultrafiltration, significantly exceeds 40%, substantial amounts of phase reversal will take place during ultrafiltration. Thus, it is possible to achieve the phase reversal, especially in regard to the lower emulsion ratios, entirely during ultrafiltration.
However, additional shear is often required to achieve the desired degree of phase reversal, especially in regard to the higher emulsion ratios, and this additional shear is provided by the homogenization step, where further phase reversal takes place. In addition, even if all of the desired phase reversal takes place during ultrafiltration, the composition should nevertheless be homogenized, or otherwise the product will not be of the quality and uniformity normally desired.
Accordingly, while the ultrafiltration step is referred to as a concentration step, in fact, significant or even substantially all of the required phase reversal may take place in that step. Likewise, while the homogenization step is characterized and a means of achieving phase reversal, little or most or even all of the phase reversal may take place during homogenization. Thus, it is the combination of ultrafiltration and homogenization which achieves the required phase reversal and the completion of the product.
To complete the composition, only conventional ingredients need be added. These conventional ingredients can include flavorings, such as salt, colorings, e.g. FDA yellows, and the like.
The composition is then packaged in any convenient package by any conventional packaging apparatus. While pasteurization may be performed during packaging, if a pasteurizing step is desired, it is preferred that the pasteurizing step take place prior to homogenization. Thus, the pasteurizing step, if desired, may take place at any point in the process, preferably prior to homogenization, and more preferably in the feed step, although pasteurization anytime prior to packaging may be used.
The composition can be molded, for example, into one pound blocks, quarter pound sticks, or packaged in tubs in the conventional manner.
.sup.T he characteristics of the composition will somewhat depend on the ratio of the water-in-oil emulsion to the oil-in-water emulsion. With lower ratios, the spreadability will increase but the taste, texture and mouth feel will not be as close to that of butter as would be higher ratios. On the other hand, as the ratio is increased, the taste, texture and mouth feel will be more similar to butter, but the spreadability thereof will decrease. The optimum combination of these properties is where the ratio is about 7:3 to 8:2, and this will produce a taste, texture and mouth feel very similar to butter, while providing good spreadability.
.sup.A s can, therefore, be appreciated from the description of the invention in the prior patent, a substantial improvement in the art of butter spreads is provided by the composition and method of that prior patent. However, the composition of that prior patent does require that the fat content of that composition be only butter fat. As specifically brought in the prior patent, all of the fat, which is to ultimately reside in the spreadable composition, must be in the feed to the process, and since the feed to the process is a liquid dairy product, which, of course, will only contain butter fat, the resulting composition will contain only butter fat. For certain dietary conditions, it is advisable to control the butter-fat intake, and for that reason, the spreadable composition of the prior patent has some restricted utilities.
In addition, the spreadable composition of the prior patent is so arranged that it will not oil-out at elevated temperatures, and, thus, it is not substantially effective for use in most cooked foods. For example, the spreadable composition of the prior patent is not recommended for use in baking or in frying, since the higher temperature melting characteristics of that composition are unfavorable for such uses.
It would, therefore, be an advantage to provide a modified composition of the prior patent with modifications which not only reduce the amount of butter fat in the composition, but which also provide an ability for using the modified composition in cooking, especially in frying.